Apparatus for dewaxing hydrocarbon oils



B. H LINCOLN APPARATUS FOR DEWAXING HYDROCARB ON OILS April 12; 1938.

Filed Feb. 21, 1936 2 Sheets-Sheet l kuwhmkksu WKMM Q N QM INVENTOR.

n W 2m 7 F V e A 5% B. H. LINCOLN APPARATUS FOR DEWAXING HYDROCARBON OILS April 12,, 1938.

Filed Feb. 21, 1936 2 Sheets-Sheet 2 INVENTOR Patented Apr. 1 2, 1 938 2,1 ,809

UNITED STATES PTENT OFICE APPARATUS FOR DEWAXING HYDRO- CARBON OILS Bert H. Lincoln, Ponca City, Okla, assignor to Continental Oil Company, Ponca City, Okla., a corporation of Delaware Application February 21, 1936, Serial No. 65,089

2 Claims. (01. 196-19) My invention relates to a method and appashown diagrammatically at 8, through line 9. ratus'for'dewaxing hydrocarbon oils, and more The cooling medium leaves heat exchanger I particularly to a method employing a photothrough line I and passesback to the refrigera- V electric control. tion' system for recycling. The further chilled oil 'In theoperation of a dewaxing process employsolution leaves heat exchanger 1 through line I I, ing centrifugal separation'of precipitated wax, it and passes through heat exchangers I2 and I3 in is not possible by diluting and chilling stocks of heat exchange with a refrigera t adapted to oil bearingwax to consistently dewax to a cerchill the-oil solution to a low temperature, as for tain prescribed cold test. 'In'theoperation of the example 50 F. The refrigerant may be 3111- dewaxing system there is'apparently considerable monies 1701 e a p a y gas adapted be '10 Wax 'held on the chilling coils which will. fall off compressed by compressor I4, pass through heat after acertainweighthas been piled up, giving exchanger I5, from which the cool compressed rea very high concentration of wax at the cenfrigerant leaves through line I6 to be expanded trifugal separators. The centrifugal separators through'va ve through the heat exchangers I2 l5 'aredesigned' and equipped for separating preand I3 for refrigerating the wax bearing o cipitated wax from a solution of oil in varying solution. The chilling of the oil solution to a low percentages between certain prescribed and defit pe precipitates t We out of solunite limits. tion. In appearance the'solution is cloudy or Whena solution of greater wax content than hazy, the haze being caused by small wax parthat forwhich themachine is designed is charged tioles. These wax particles are of greater gravity to'a centrifugal separator, complete separation than the solution i wh ch t ey e p d is'not always obtained. When this occurs, the s permits a! separation to made. y e discharge from the wax-free oil outlet of the trifugal for Th solution ing precipitated machine ishazy' or cloudy, the amount of cloud Wax leaves heat exchanger I3through line I8 and 5 depending-upon the wax content. The wax-free passes'into amanifold I9, from which it is withoilwhich' haspassed through the machine satisdrawn through a ser s of p p 22 factorily, will in such cases be contaminated by controlled by Va es 5, 26 and 27. While I oil which is not wax-free or properly dewaxed. e Shown e Centrifuges, it is to be under- One object of my invention is toprovide a stoodthat any suitablenumber may be employed.

'3) method 'and'apparatus inwhich improperly de- One plant, for example, may employ thirty-six waxed oil is prevented from contaminating a bulk centrifuges. One ormore chilling tanks may be of dewaxed oil solution which has been properly placed in line I8 if necessary. dewaxed. The valves 24, 25, 26 and 21 are urged to closed Other and further objects of my invention will position by springs, and are normally held in open appear from the following description. position by'the action of electro-magnets. The 35 -40 various views:

In the accompanying drawings which form part control mechanism is contained in housings 28, of=the instant specification and which are to be 29, tfland'iil. The oilpassing through thepipes read in conjunction therewith, and in which like 20, 2|, 22'and'23, entersthe respective bowls of numerals are used to indicate like parts in the centrifuges 32, 33, 34 and 35. The centrifuges are drivenby electric motors 36, 37, 38 and 39, 4

Fig. 1 is a diagrammatic view of a dewaxing which are controlled by electro-magnetic operated system embodying one modification of-theappaswitches contained in housings 40, 4|, 42 and lS. ratus of my invention and adapted to carry out The valve controls 28, 29, 30 and 3| and the motor the process of my invention. controls m, 4|, 42 and 43, are governed by photo- 45 Fig. 2 is a diagrammatic viewof the electrical electric relays contained'in housings M, 45, 46 45 connections of-the apparatus shown in Fig. 1. and ll.

Awax bearing oil suitably diluted with a diluent In the diagrammatic view of Fig. 1, only the is charged through line I from any suitable source outlet for the dewaxed oil solution is shown, and and passes through heat exchangers 2 and 3, in appears as pipes 48, 49, 50 and 5|. These pipes 50 heat exchange with chilled dewaxed oil solution pass through jackets 52!, through which a re- 50 on its way to storage tank 4. The partially cooled frigerating medium is passed through lines 53, oil solution leaves heat exchanger 3 through line leaving jackets 52 through lines 54. The de- 5 and passes through heat exchangers 6 and I in waxed oil solution passes from heat exchangers heat exchange with a cold medium, which may be 52, through lines 55, which pass into a common 55 chilled brine, passing from a refrigeration system, manifold 56. Interposed in lines 55 are fittings 55 51 fitted with windows adapted to pass a beam of light from light sources in suitable housings 58, as can readily be seen by reference to Fig. 2. The dewaxed oil solution passes from manifold 55 through line 59 through heat exchangers 2 and 3 to storage tank 4.

Referring now to Fig. 2, an incandescent lamp 5!) is lighted by current furnished through conductors 5i and 52. A beam of light 68' passes through windows 63 and 64 provided in fitting 51, upon photoelectric tube 55 having a cathode 55, and an anode 5?. Main line wires 58 and 59 are connected to an alternating current supply. The primary 10 of a transformer is connected across the main line. The primary is provided with three secondaries H, 12 and 13. The secondary H is connected at one end to the anode I 6'! of the photoelectric tube 65 and at the other end to one side of a condenser 14, the other side of which is connected to the cathode 66 by a conductor '55. The secondary 12 is connected across the filament 15 of a triode H. The center tap of secondary i2 is connected to the arm 18 of a potentiometer provided with a resistance 19, and is adapted to adjust the bias upon the photoelectric tube 65, and to one end of the secondary 13 through conductor 80. Secondary 13 is in the plate circuit of the triode T! in series with electromagnets Bi and 82 of relays controlling the switch 40 of the motor 35, and the electro-magnet, controlling valve 24, in housing 28.

A condenser 83 for by-passing high frequency currents is shunted across relay coils BI and 82. The output of photoelectric tube 55 is impressed upon the grid of triode Ti through conductor BI and resistance 92.

In operation, as long as the dewaxed oil solution passing through fitting 5'! is clear of haze or cloud, the light beam 68 will pass through the oil solution in sufficient intensity so that the plate current of triode I1 is able to magnetize electromagnets 8| and 82 to attract armatures 93 and 94, to close the circuit across contact points 95 and 96, and 91 and 98 respectively. The closing of the circuit across contacts 95 and 96 actuates the motor switch within the housing 40 to start the motor 36. The closing of the circuit across contact points 91 and 98 actuates the electromagnet in housing 28 against the action of a spring to open valve 24. As long as the oil solution is clear the motor will be running and the valve 24 will remain open. It will be obvious, of course, that in starting with no oil solution in pipe 55 no resistance to the passage of light beam 58 is encountered, and the condition described will take place.

When the oil leaving the centrifuge 32 becomes clouded, a resistance to the passage of light will occur, which will reduce the light beam in intensity. When this occurs the output of photoelectric tube 65 will drop making the grid less positive, thus reducing the plate current, demagnetizing to an extent electro-magnets 8| and 82 and permitting springs 99 and IE0 to pull armatures 93 and 94 to a position breaking the circuit across contact points 55 and 96, and 91 and 98, respectively, thus shutting off the motor 36 and closing valve 24.

The value at which this action will take place can be adjusted by adjusting the position of arm Z8 upon potentiometer I9 and varying the bias upon the anode of the photoelectric tube 65. In practice I have found that an undissolved wax content of from .01 to .2 of 1 percent or more by weight will be sufficient to give satisfactory manipulation of the photoelectric relay.

It will be observed that I have accomplished the objects of my invention. A centrifuge plant might produce 5,000 barrels of wax-free oil over a period of time, and the entire production may be ruined by an hours unsuccessful operation by a single centrifuge. It is impossible to determine by laboratory tests the condition of the operation of the centrifuge in a period ofless than 1 to 2 hours, and by the use of my invention I preclude the possibilityof ruining a batch of dewaxed oil solution by the faulty operation of one or more centrifuge machines. It is of importance that the oil solution passing through the fitting 51 be of approximately the same low temperature as it leaves the centrifuge so that the presence of wax will appear in the form of a haze. It is for this reason I provide chilling jackets 52. The small amount of haze in oil will disappear when the temperature is allowed to rise.

It will be understood that my invention may be employed on any separator of wax regardless of solvent or means of separation, provided the unseparated wax appears as a haze in the oilsolvent. For example, certain heavy halogenated solvents are used in dewaxing oils by centrifugal force and my control method is applicable to these pressures. My equipment may also be used on a wax press separator.

It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of my claims, It is further obvious that various changes may be made in details within the scope of my claims without departing from the spirit of my invention. It is therefore, to be understood that my invention is not to be limited to the specific details shown and described.

Having thus described my invention, what I claim is:

1. In a dewaxing apparatus a centrifuge for separating precipitated wax from an oil solution, a line for conducting oil solution containing precipitated Wax to said centrifuge, a valve controlling said line, a motor for driving said centrifuge, an eduction line from said centrifuge for Withdrawing dewaxed oil solution and means responsive to the transparency of the dewaxed oil solution leaving the centrifuge for controlling said valve and said motor.

2. A dewaxing apparatus as in claim 1 wherein said eduction line is provided with heat exchange means for chilling the dewaxed oil solution leaving said centrifuge.

BERT H. LINCOLN. 

